replaceing the ignition on 2005 Chevrolet Impala

the radio does not turn off and i think the steering wheel will not lock,all lights turn off and elec. door locks work. so how involved is it to change the ignition ?? fixed income so i need to do my self,if possible ??

after i drove it on a erran,got hm. and working right now , so by what little i've read,it's the ignition lock,that has misfired,maybe not wwhole ignition. ?? it's a two part ignition or could be ,huh??